Why Do Arms Get Fat?

Andrea Cespedes

Upper-arm exercises may help restore some of the muscle firmness.
(Image: napatcha/iStock/Getty Images)

Flabby upper arms may make you feel self-conscious when you bare your arms in summer clothes. Although where you store fat is largely a matter of genetics, some people's bodies, especially women's, use the arms as a stubborn fat depot. To lose weight in the arms, adopt a comprehensive weight-loss strategy that helps you slim down overall. The fat on your arms may hang on longer than fat from other areas, but it will eventually yield to classic weight-loss efforts.

Weight-Gain Basics

Arms get fat when you gain weight from eating more calories than you burn. A 3,500-calorie surplus, even accrued over several months, can lead to a 1-pound weight gain. If you eat just an extra 100 calories per day, you'll gain almost 1 pound per month. That's just one-half of a large chocolate chip cookie, an extra ounce of cheese or a skinny vanilla latte in addition to what you usually eat daily.

When you gain weight, where it goes depends largely on your body shape. People usually gain weight in the hips, thighs and abdomen but can also develop extra fat in the arms and lower legs. You can gain fat anywhere your body has an abundance of fat cells.

Calorie Sources for Fat Gain

Eating too much sugar and refined grains -- such as candy, baked goods, white bread, white pasta and soda -- causes you to easily surpass your calorie needs. Sugar also has little nutrition and digests quickly, causing your body to release the hormone insulin. Habitual high-sugar consumption leads to increased levels of insulin. When your insulin level is high, your body tends to store calories as fat, rather than using fat for energy. If your body type tends to put on weight in the arms, then you'll see weight gain there. You'll likely notice other areas of your body growing in size, too.

Low Testosterone Levels and Fat Gain

Stress, a poor diet, a sedentary lifestyle and inadequate sleep can cause your testosterone levels to plummet. Testosterone is a male sex hormone, but women do have a baseline level. Testosterone in both sexes supports your sex drive, energy and ability to build muscle. If your numbers are lower than they should be, your body may efficiently store fat and resist muscle development. Your arms may be the victim of the resulting flabbier, less-toned physique.

Naturally regulate your testosterone levels by consuming adequate amounts of protein from organic meats and dairy, fish, eggs, beans and legumes. If you're actively trying to drop weight, go for about 0.55 gram per pound of body weight, as this amount helps support satiety and good health, according to a study published in a 2012 issue of the British Journal of Nutrition. Adopt a workout routine that addresses every muscle group and involves lifting weights that feel heavy by the last couple of repetitions in a set of eight to 12. Mix up your weekly cardio workouts by adding in a session or two of intervals, which involve alternating high-intensity bursts with low-intensity ones. Actively reduce stress by attending a yoga class, meditating and delegating duties at work or home. A quality seven to nine hours of sleep per night also helps weight loss by regulating hunger hormones and giving you energy for workouts.

Losing Arm Fat

As you get older, your muscles may atrophy, contributing to some of the wiggling at the back of your arm. Upper-arm exercises may help restore some of the muscle firmness. And, even if you have weight to lose, training your arms will reveal toned, taut "guns" when you do slim down. Triceps extensions, kickbacks and biceps curls won't attack the fat that eclipses the muscles, however.

The only way to lose arm flab is with a comprehensive weight-loss program. If your arms are one of the places at which you've noticed recent weight gain, it'll also be one of the first areas where you'll lose weight. Use a reduced-calorie diet and more movement to help you create a calorie deficit to drop pounds. A deficit of 500 to 1,000 calories per day from what you need to maintain your weight helps you lose 1 to 2 pounds per week. You'll notice weight disappear from your arms and other areas of fat deposition.